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https://www.readbyqxmd.com/read/28729396/acute-volume-loading-exacerbates-direct-ventricular-interaction-in-a-model-of-copd
#1
William Spencer Cheyne, Alexandra Mackenzie Williams, Megan I Harper, Neil Derek Eves
Volume loading increases left ventricular (LV) stroke volume (LVSV) through series interaction but may paradoxically reduce LVSV in the presence of large increases in right ventricular (RV) afterload due to direct ventricular interaction (DVI). RV afterload is often increased in COPD as a result of pathological changes to respiratory mechanics, namely increased negative intrathoracic pressure (nITP), dynamic lung hyperinflation (DH) and increased pulmonary vascular resistance (PVR). These hallmarks of COPD negatively impact LV hemodynamics in normovolemia...
July 20, 2017: Journal of Applied Physiology
https://www.readbyqxmd.com/read/28729141/effects-of-transjugular-intrahepatic-portosystemic-shunt-tips-on-blood-volume-distribution-in-patients-with-cirrhosis
#2
Troels M Busk, Flemming Bendtsen, Jens H Henriksen, Stefan Fuglsang, Jens O Clemmesen, Fin S Larsen, Søren Møller
BACKGROUND: Cirrhosis is accompanied by portal hypertension with splanchnic and systemic arterial vasodilation, and central hypovolaemia. A transjugular intrahepatic portosystemic shunt (TIPS) alleviates portal hypertension, but also causes major haemodynamic changes. AIMS: To investigate effects of TIPS on regional blood volume distribution, and systemic haemodynamics. METHODS: Thirteen cirrhotic patients had their regional blood volume distribution determined with gamma-camera technique before and after TIPS...
June 27, 2017: Digestive and Liver Disease
https://www.readbyqxmd.com/read/28709666/novel-rotational-speed-modulation-system-used-with-venoarterial-extracorporeal-membrane-oxygenation
#3
Noritsugu Naito, Takashi Nishimura, Kei Iizuka, Yutaka Fujii, Yoshiaki Takewa, Akihide Umeki, Masahiko Ando, Minoru Ono, Eisuke Tatsumi
BACKGROUND: Femoral venoarterial extracorporeal membrane oxygenation (VA-ECMO) is widely used to maintain blood flow in patients with cardiogenic shock. However, retrograde blood flow increases left ventricular (LV) afterload during femoral VA-ECMO. Additional support by means of an intraaortic balloon pump (IABP) alleviates LV afterload but is associated with significant adverse events. We previously developed a system for rotational speed modulation in synchrony with the native cardiac cycle, for use with implantable continuous-flow LV assist devices...
July 11, 2017: Annals of Thoracic Surgery
https://www.readbyqxmd.com/read/28707021/the-response-to-trendelenburg-position-is-minimally-affected-by-underlying-hemodynamic-conditions-in-patients-with-aortic-stenosis
#4
Abraham Sonny, Daniel I Sessler, Jing You, Babak Kateby Kashy, Sheryar Sarwar, Akhil K Singh, Shiva Sale, Andrej Alfirevic, Andra E Duncan
PURPOSE: Trendelenburg positioning is commonly used to temporarily treat intraoperative hypotension. The Trendelenburg position improves cardiac output in normovolemic or anesthetized patients, but not hypovolemic or non-anesthetized patients. Therefore, the response to Trendelenburg positioning may vary depending on patient population or hemodynamic conditions. We thus tested the hypothesis that the effectiveness of the Trendelenburg position, as indicated by an increase in cardiac output, improves after replacement of a stenotic aortic valve...
July 13, 2017: Journal of Anesthesia
https://www.readbyqxmd.com/read/28703274/pterostilbene-reduces-oxidative-stress-prevents-hypertrophy-and-preserves-systolic-function-of-right-ventricle-in-cor-pulmonale-model
#5
Denise Dos Santos Lacerda, Patrick Türck, Bruna Gazzi de Lima-Seolin, Rafael Colombo, Vanessa Duarte Ortiz, Jéssica Hellen Poletto Bonetto, Cristina Campos-Carraro, Sara Elis Bianchi, Adriane Belló-Klein, Valquiria LinckBassani, Alex Sander da Rosa Araujo
BACKGROUND AND PURPOSE: In cor pulmonale, the increased afterload imposed on the right ventricle (RV) generates a maladaptive response, impairing the contractile cardiac function. Oxidative mechanisms play an important role in the pathophysiology and progression of this disease. The administration of pterostilbene (PTS), a phyto-phenol with antioxidant potential, may represent a therapeutic alternative. In the present study, the objective was to evaluate the effect of PTS complexed with hydroxypropyl-β-cyclodextrin (HPβCD) on hypertrophy, contractile function and oxidative parameters in the RV of rats with pulmonary hypertension induced by monocrotaline administration...
July 12, 2017: British Journal of Pharmacology
https://www.readbyqxmd.com/read/28702845/regulation-of-cardiac-ca-2-and-ion-channels-by-shear-mechanotransduction
#6
REVIEW
Joon-Chul Kim, Min-Jeong Son, Jun Wang, Sun-Hee Woo
Cardiac contraction is controlled by a Ca(2+) signaling sequence that includes L-type Ca(2+) current-gated opening of Ca(2+) release channels (ryanodine receptors) in the sarcoplasmic reticulum (SR). Local Ca(2+) signaling in the atrium differs from that in the ventricle because atrial myocytes lack transverse tubules and have more abundant corbular SR. Myocardium is subjected to a variety of forces with each contraction, such as stretch, shear stress, and afterload, and adapts to those mechanical stresses...
July 12, 2017: Archives of Pharmacal Research
https://www.readbyqxmd.com/read/28701528/blood-pressure-and-arterial-load-after-transcatheter-aortic-valve-replacement-for-aortic-stenosis
#7
MULTICENTER STUDY
Brian R Lindman, Catherine M Otto, Pamela S Douglas, Rebecca T Hahn, Sammy Elmariah, Neil J Weissman, William J Stewart, Girma M Ayele, Feifan Zhang, Alan Zajarias, Hersh S Maniar, Hasan Jilaihawi, Eugene Blackstone, Khaja M Chinnakondepalli, E Murat Tuzcu, Martin B Leon, Philippe Pibarot
BACKGROUND: After aortic valve replacement, left ventricular afterload is often characterized by the residual valve obstruction. Our objective was to determine whether higher systemic arterial afterload-as reflected in blood pressure, pulsatile and resistive load-is associated with adverse clinical outcomes after transcatheter aortic valve replacement (TAVR). METHODS AND RESULTS: Total, pulsatile, and resistive arterial load were measured in 2141 patients with severe aortic stenosis treated with TAVR in the PARTNER I trial (Placement of Aortic Transcatheter Valve) who had systolic blood pressure (SBP) and an echocardiogram obtained 30 days after TAVR...
July 2017: Circulation. Cardiovascular Imaging
https://www.readbyqxmd.com/read/28699120/valve-related-modes-of-pump-failure-in-collecting-lymphatics-numerical-and-experimental-investigation
#8
C D Bertram, C Macaskill, M J Davis, J E Moore
Lymph is transported along collecting lymphatic vessels by intrinsic and extrinsic pumping. The walls have muscle of a type intermediate between blood-vascular smooth muscle and myocardium; a contracting segment between two valves (a lymphangion) constitutes a pump. This intrinsic mechanism is investigated ex vivo in isolated, spontaneously contracting, perfused segments subjected to controlled external pressures. The reaction to varying afterload is probed by slowly ramping up the outlet pressure until pumping fails...
July 11, 2017: Biomechanics and Modeling in Mechanobiology
https://www.readbyqxmd.com/read/28697895/a-neonatal-rat-model-of-increased-right-ventricular-afterload-by-pulmonary-artery-banding
#9
Shoubao Wang, Lincai Ye, Haifa Hong, Chao Tang, Minghui Li, Zhen Zhang, Jinfen Liu
OBJECTIVE: To construct a neonatal rat model of increased right ventricular (RV) afterload for studying the pathophysiological remodeling of the right ventricle in patients with congenital heart disease with increased RV afterload. METHODS: Surgery was performed within 6 hours after birth. Horizontal thoracotomy was performed by dissecting the intercostal muscles and splitting the sternum. The PA was then banded with 11-0 nylon thread. At postnatal day 7 (P7), constriction of PA was confirmed by echocardiography...
June 13, 2017: Journal of Thoracic and Cardiovascular Surgery
https://www.readbyqxmd.com/read/28691283/a-soft-total-artificial-heart-first-concept-evaluation-on-a-hybrid-mock-circulation
#10
Nicholas H Cohrs, Anastasios Petrou, Michael Loepfe, Maria Yliruka, Christoph M Schumacher, A Xavier Kohll, Christoph T Starck, Marianne Schmid Daners, Mirko Meboldt, Volkmar Falk, Wendelin J Stark
The technology of 3D-printing has allowed the production of entirely soft pumps with complex chamber geometries. We used this technique to develop a completely soft pneumatically driven total artificial heart from silicone elastomers and evaluated its performance on a hybrid mock circulation. The goal of this study is to present an innovative concept of a soft total artificial heart (sTAH). Using the form of a human heart, we designed a sTAH, which consists of only two ventricles and produced it using a 3D-printing, lost-wax casting technique...
July 10, 2017: Artificial Organs
https://www.readbyqxmd.com/read/28680587/resistance-over-compliance-describes-right-ventricular-afterload-better-than-resistance-compliance-time-a-friendly-amendment
#11
Thenappan Thenappan, Stephen L Archer, E Kenneth Weir
No abstract text is available yet for this article.
March 2017: Pulmonary Circulation
https://www.readbyqxmd.com/read/28680577/hypoxia-induced-pulmonary-hypertension-in-type-2-diabetic-mice
#12
Minglin Pan, Ying Han, Rui Si, Rui Guo, Ankit Desai, Ayako Makino
Hypoxia-induced pulmonary hypertension (HPH) is a progressive disease that is mainly caused by chronic exposure to high altitude, chronic obstructive lung disease, and obstructive sleep apnea. The increased pulmonary vascular resistance and increased pulmonary arterial pressure result in increased right ventricular afterload, leading to right heart failure and increased morbidity. There are several clinical reports suggesting a link between PH and diabetes, insulin resistance, or obesity; however, it is unclear whether HPH is associated with diabetes as a progressive complication in diabetes...
March 2017: Pulmonary Circulation
https://www.readbyqxmd.com/read/28679970/clinical-significance-of-pulmonary-arterial-capacitance-calculated-by-echocardiography-in-patients-with-advanced-heart-failure
#13
Yuki Saito, Tomohito Ohtani, Hidetaka Kioka, Toshinari Onishi, Yasumasa Tsukamoto, Kei Nakamoto, Tatsunori Taniguchi, Satoshi Nakatani, Atsushi Hirayama, Yasushi Sakata
BACKGROUND: Advanced left heart failure (HF) often accompanies post-capillary pulmonary hypertension related to RV afterload. Although pulmonary arterial capacitance (PAC), a measure of pulmonary artery compliance, reflects right ventricular (RV) afterload, the clinical utility of PAC obtained by echocardiography (echo-PAC) is not well established in advanced HF.Methods and Results:We performed right heart catheterization in advanced HF patients (n=30), calculating echo-PAC as stroke volume/(tricuspid regurgitation pressure gradient-pulmonary regurgitation pressure gradient)...
July 4, 2017: Circulation Journal: Official Journal of the Japanese Circulation Society
https://www.readbyqxmd.com/read/28679681/acute-effects-of-angiotensin-converting-enzyme-inhibition-versus-angiotensin-ii-receptor-blockade-on-cardiac-sympathetic-activity-in-patients-with-heart-failure
#14
Eduardo R Azevedo, Susanna Mak, John S Floras, John D Parker
The beneficial effects of angiotensin converting enzyme (ACE) inhibitors and angiotensin II (AII) receptor antagonists in patients with heart failure secondary to reduced ejection fraction (HFrEF) are felt to result from prevention of the adverse effects of AII on systemic afterload and renal homeostasis. However, AII can activate the sympathetic nervous system and part of the beneficial effects of ACE inhibitors and AII antagonists may result from their ability to inhibit such activation. We examined the acute effects of the ACE inhibitor captopril (25 mg, n = 9) and the AII receptor antagonist losartan (50 mg, n = 10) on hemodynamics as well as total body and cardiac norepinephrine spillover in patients with chronic HFrEF...
July 5, 2017: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology
https://www.readbyqxmd.com/read/28679580/use-of-an-ipad-app-to-simulate-pressure-volume-loops-and-cardiovascular-physiology
#15
Staci Leisman, Daniel Burkhoff
The purpose of this laboratory exercise is to model the changes in preload, afterload, and contractility on a simulated pressure-volume loop and to correlate those findings with common measurements of clinical cardiovascular physiology. Once students have modeled these changes on a healthy heart, the students are asked to look at a simulated case of cardiogenic shock. Effects on preload, contractility, and afterload are explored, as well as the hemodynamic effects of a number of student-suggested treatment strategies...
September 1, 2017: Advances in Physiology Education
https://www.readbyqxmd.com/read/28679570/cardiopulmonary-physiology-why-the-heart-and-lungs-are-inextricably-linked
#16
Kevin Verhoeff, Jamie R Mitchell
Because the heart and lungs are confined within the thoracic cavity, understanding their interactions is integral for studying each system. Such interactions include changes in external constraint to the heart, blood volume redistribution (venous return), direct ventricular interaction (DVI), and left ventricular (LV) afterload. During mechanical ventilation, these interactions can be amplified and result in reduced cardiac output. For example, increased intrathoracic pressure associated with mechanical ventilation can increase external constraint and limit ventricular diastolic filling and, therefore, output...
September 1, 2017: Advances in Physiology Education
https://www.readbyqxmd.com/read/28679058/pharmacological-inhibition-of-mtor-kinase-reverses-right-ventricle-remodeling-and-improves-right-ventricle-structure-and-function-in-rats
#17
Andressa Pena, Ahasanul Kobir, Dmitry Goncharov, Akiko Goda, Tatiana V Kudryashova, Arnab Ray, Rebecca Vanderpool, Jeffrey Baust, Baojun Chang, Ana L Mora, John Gorcsan Iii, Elena A Goncharova
Pulmonary arterial hypertension (PAH) is characterized by pulmonary vascular remodeling, increased pulmonary artery pressure (PAP), right heart afterload and death. Mechanistic target of rapamycin (mTOR) promotes smooth muscle cell proliferation, survival and pulmonary vascular remodeling via two functionally distinct complexes, mTORC1 (supports cell growth) and mTORC2 (promotes cell survival), and dual mTORC1/mTORC2 inhibition selectively induces PAH PAVSMC apoptosis and reverses pulmonary vascular remodeling...
July 5, 2017: American Journal of Respiratory Cell and Molecular Biology
https://www.readbyqxmd.com/read/28669395/afterload-dependence-of-right-ventricular-myocardial-strain
#18
Leah Wright, Kazuaki Negishi, Nathan Dwyer, Sudhir Wahi, Thomas H Marwick
BACKGROUND: Right ventricular (RV) free wall strain (RVFWS) is a feasible method for quantitation and follow-up of RV function and may have benefits over traditional markers such as fractional area change. However, like all ejection phase parameters, RVFWS is difficult to assess in the presence of changing afterload. The aim of this study was to compare RVFWS and traditional RV function parameters for tracking progress of RV function in patients with pulmonary arterial hypertension (PAH) over a range of pulmonary artery systolic pressure (PASPs)...
July 2017: Journal of the American Society of Echocardiography
https://www.readbyqxmd.com/read/28655868/double-peripheral-venous-and-arterial-cannulation-for-extracorporeal-membrane-oxygenation-in-combined-septic-and-cardiogenic-shock
#19
Markus Kredel, Steffen Kunzmann, Paul-Gerhardt Schlegel, Matthias Wölfl, Peter Nordbeck, Christoph Bühler, Christopher Lotz, Philipp M Lepper, Johannes Wirbelauer, Norbert Roewer, Ralf M Muellenbach
BACKGROUND The use of venoarterial extracorporeal membrane oxygenation (va-ECMO) via peripheral cannulation for septic shock is limited by blood flow and increased afterload for the left ventricle. CASE REPORT A 15-year-old girl with acute myelogenous leukemia, suffering from severe septic and cardiogenic shock, was treated by venoarterial extracorporeal membrane oxygenation (va-ECMO). Sufficient extracorporeal blood flow matching the required oxygen demand could only be achieved by peripheral cannulation of both femoral arteries...
June 28, 2017: American Journal of Case Reports
https://www.readbyqxmd.com/read/28648626/mechanosensitivity-of-microdomain-calcium-signalling-in-the-heart
#20
REVIEW
Patrick Schönleitner, Uli Schotten, Gudrun Antoons
In cardiac myocytes, calcium (Ca(2+)) signalling is tightly controlled in dedicated microdomains. At the dyad, i.e. the narrow cleft between t-tubules and junctional sarcoplasmic reticulum (SR), many signalling pathways combine to control Ca(2+)-induced Ca(2+) release during contraction. Local Ca(2+) gradients also exist in regions where SR and mitochondria are in close contact to regulate energetic demands. Loss of microdomain structures, or dysregulation of local Ca(2+) fluxes in cardiac disease, is often associated with oxidative stress, contractile dysfunction and arrhythmias...
June 22, 2017: Progress in Biophysics and Molecular Biology
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